Lecture 14

Question 1

Hypothalamus- Pituitary

Answer 1

Your pituitary gland is connected to your hypothalamus through a stalk of blood vessels and nerves (the pituitary stalk). Through that stalk, your hypothalamus communicates with the anterior pituitary lobe via hormones and the posterior lobe through nerve impulses

Question 2

The Pituitary gland is two glands fused in one

Answer 2

1. Posterior pituitary
2. Anterior pituitary

Question 3

Posterior pituitary

Answer 3

is neural tissue and secretes two neuro hormones: vasopressin (antidiuretic hormone or ADH) and oxytocin

Question 4

Anterior pituitary

Answer 4

is endocrine tissue and secretes six hormones: prolactin, thyrotropin, adrenocorticotropin, growth hormone, follicle stimulating hormone, and luteinizing hormone

Question 5

Growth hormone (GH): peptide hormone

Answer 5

• GH: 191AA
  
  • Released from anterior pituitary
  • Stimulated by GHRH
  • Inhibited by Somatostatin
• Acts in liver to stimulate IGF release

Question 6

IGFR

Answer 6

insulin-like growth factor (acts on liver to secrete IGF-1)- growth- promoting effects on almost every cell in the body

Question 7

IGFR receptor

Answer 7

tyrosine kinase

Question 8

Key Concepts for the GH (growth hormone)

Answer 8

1. Normal growth
2. Anterior pituitary secretes GH
3. GH is regulated

Question 9

Normal growth requires

Answer 9

GH, thyroid hormones, insulin, and sex hormones, Adequate nutrition and no chronic stress

Question 10

Anterior pituitary secretes GH which Stimulates…

Answer 10

IGF-1 to promote bone and soft tissue growth

Question 11

GH is regulated by…

Answer 11

Stimulated by GHRH and Inhibited GHIH (aka somatostatin)

Question 12

Thyroid hormones are made from…

Answer 12

iodine and tyrosine

Question 13

Gigantism

Answer 13

too much GH in childhood

Question 14

Acromegaly

Answer 14

too much GH in adulthood
abnormal growth of the hands, feet, and face, caused by overproduction of growth hormone by the pituitary glad

Question 15

TSH

Answer 15

thyroid stimulating hormone

Question 16

5 Factors of TSH

Answer 16

• Is a peptide hormone
  
  • It activates G-protein linked membrane receptors acting via Adenylate cyclase
  • Stimulates synthesis and activity of enzymes involved in T4 and T3 synthesis
  • Activates transcription factors: c-fos, c-myc
  • Stimulates thyroid growth

Question 17

TRH

Answer 17

thyrotropin releasing hormone

Question 18

Function of Thyroid Hormones

Answer 18

• Metabolic: (metabolic rate, oxygen consumption, heat production, protein degradation, lipolysis)
• Nervous system: (enhances speech, thinking, reflexes)
• Growth and development: (essential in children, works with GH)
• Cardiovascular: (enhances heart rate and contractility; peripheral blood flow, works in part by increasing numbers of beta adrenergic receptors + other proteins)
• Muscular: (too much causes muscle weakness)

Question 19

The Mechanism of Action of Thyroid Hormones

Answer 19

• T3 and T4 circulate in blood bound to plasma proteins
• T3 more 3-5X more potent than T4
• T4 converted to T3 in target tissues
• Both T3 and T4 bind to nuclear thyroid receptors & alter gene transcription

Question 20

Graves Disease

Answer 20

(Autoimmune disease) Abnormal antibodies against the TSH receptor are produced.

Question 21

Hyperthyroidism
(Thyroid hormone ) Causes

Answer 21

• Tumors
• thyroid-stimulating immunoglobulins (Graves’ disease)

Question 22

Hyperthyroidism
(Thyroid hormone ) Symptoms

Answer 22

goiter, nervousness, insomnia, anxiety, high heart rate, exophthalmos (Graves’ disease), weight loss.

Question 23

Hyperthyroidism
(Thyroid hormone )

Answer 23

• removal of part of the thyroid gland
• drugs blocking synthesis of T3 and T4 or block conversion of T4 to T3

Question 24

Hypothyroidism: (Thyroid hormone deficiency) causes

Answer 24

• Under active thyroid gland
  Lack of iodine in diet

Question 25

Hypothyroidism: (Thyroid hormone deficiency) symptoms

Answer 25

goiter, slowed heart rate, slowed speech, fatigue, cold-intolerance, cretinism (infants), stunted growth (infants) and weight gain.

Question 26

Hypothyroidism: (Thyroid hormone deficiency) treatments

Answer 26

exogenous thyroid hormone T4 (thyroxine)